Slideshow generating apparatus, slideshow-data generating apparatus, control methods therefor and programs for controlling same

ABSTRACT

A background image wherein areas in which still images are to be rendered have been defined is prepared. Product images are obtained by multiplying mask images and positioned still images together. The background image and the product images are added to obtain a sum image that constitutes one frame of a slideshow. A plurality of still-image portions obtained from a plurality of still images in one frame are contained in the sum image. An advanced slideshow is thus obtained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a slideshow generating apparatus, an apparatusfor generating slideshow data, as well as methods and programs forcontrolling such apparatus.

2. Description of the Related Art

A slideshow presents a display of still images of a plurality of framesin order. Such a slideshow may be a basic function of an operatingsystem and can also display background images of a number of frames,which have been stored in a folder, in the form of a slideshow. Afurther example of the prior art generates a slideshow that can bedisplayed using a DVD (Digital Versatile Disk) player (see thespecification of Japanese Patent Application Laid-Open No. 2004-194338).

In any case, however, the prior art has not given consideration to thegeneration of a highly sophisticated slideshow.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to generate a highlysophisticated slideshow.

According to a first aspect of the present invention, the foregoingobject is attained by providing a slideshow generating apparatuscomprising: a background moving-image storage device for storingbackground moving-image data representing a background moving imagecomposed of a number of frames of a background image wherein an area inwhich a still image is rendered has been defined as a mask area; astill-image data input device for inputting still-image data; a scenariodata storage device for storing scenario data that defines a positioncorresponding to the mask area in the background image, the positionbeing one at which the still image represented by the still-image datathat has been input from the still-image data input device is rendered;a positioning device (positioning means) for positioning the stillimage, which is represented by the still-image data that has been inputfrom the still-image data input device, at the position represented bythe scenario data stored in the scenario data storage device; amask-image data storage device for storing mask-image data representinga mask image in which a still-image rendering area has been defined inassociation with the mask area of the background image, an area fromwhich the still-image rendering area has been excluded being defined asa mask area; and a moving-image combining device (moving-image combiningmeans) for generating moving-image data for display by repeatedlyexecuting, with regard to the number of frames of the background image,processing that combines the background image constituting thebackground moving image represented by the background moving-image datathat has been stored in the background moving-image data storage device,the still image that has been positioned by the positioning device, andthe mask image represented by the mask-image data that has been storedin the mask image-data storage device.

The first aspect of the present invention also provides a control methodsuited to the above-described slideshow generating apparatus.Specifically, the first aspect of the present invention provides amethod of controlling a slideshow generating apparatus, comprising thesteps of: storing background moving-image data representing a backgroundmoving image composed of a number of frames of a background imagewherein an area in which a still image is rendered has been defined as amask area; storing mask-image data representing a mask image in which astill-image rendering area has been defined in association with the maskarea of the background image, an area from which the still-imagerendering area has been excluded being defined as a mask area; inputtingstill-image data; storing scenario data that defines a positioncorresponding to the mask area in the background image, the positionbeing one at which the still image represented by the still-image datathat has been input is rendered; positioning the still image, which isrepresented by the still-image data that has been input, at the positionrepresented by the scenario data stored; and generating moving-imagedata for display by repeatedly executing, with regard to the number offrames of the background image, processing that combines the backgroundimage constituting the background moving image represented by thebackground moving-image data that has been stored, the still image thathas been positioned, and the mask image represented by the mask-imagedata that has been stored.

The first aspect of the present invention also provides a program forimplementing the above-described method of controlling the slideshowgenerating apparatus.

In accordance with the first aspect of the present invention, backgroundmoving-image data is stored. The background moving-image data representsa background moving image composed of a number of frames of a backgroundimage wherein an area in which a still image is rendered has beendefined as a mask area. (In a case where an image has been superimposed,the area is one in which the superimposed image is displayed as is. Thisis a so-called “black area” the level of which is 0.) Further, scenariodata that defines a position at which the still image is rendered in thebackground image is stored. The still image is positioned at theposition defined by the scenario data. Furthermore, mask-image data isstored. The mask-image data represents a mask image in which astill-image rendering area has been defined in association with the maskarea, an area from which the still-image rendering area has beenexcluded being defined as a mask area. Processing for combining(superimposing) the background image, the positioned still image and themask image is executed repeatedly with regard to the number of frames ofbackground image constituting the background moving image, wherebymoving-image data for display is generated.

In accordance with the first aspect of the present invention, displaymoving-image data representing a slideshow in which a desired stillimage is displayed upon being positioned in a mask area of a backgroundimage can be obtained. By preparing a plurality of frames of mask-imagedata and a plurality of frames of still images, the plurality of framesof still images can be displayed in one frame, thereby making itpossible to obtain a sophisticated slideshow.

By way of example, the moving-image combining device includes amultiplying circuit for multiplying the mask image and the still imagethat has been positioned by the positioning device, thereby generating aproduct image; an adding circuit for adding the background image and theproduct image generated by the multiplying circuit; and a controller forcontrolling the multiplying circuit and the adding circuit so as torepeat, with regard to the number of frames of the background image,multiplication processing performed in the multiplying circuit andaddition processing performed in the adding circuit.

According to a second aspect of the present invention, the foregoingobject is attained by providing an apparatus for generating slideshowdata, comprising: a background moving-image data generating device(background moving-image data generating means) for generatingbackground moving-image data wherein an area in which a still image isrendered is defined as a mask area in a number of frames of a backgroundimage constituting a background moving image; and a mask-image datagenerating device for defining a still-image rendering area inassociation with the mask area defined in the background imageconstituting the background moving image represented by the backgroundmoving-image data generated by the background moving-image datagenerating device, and generating mask-image data representing a maskimage wherein an area from which the still-image rendering area has beenexcluded is defined as a mask area.

The second aspect of the present invention also provides a controlmethod suited to the above-described apparatus for generating slideshowdata. Specifically, the second aspect of the present invention providesa method of controlling a slideshow-data generating apparatus,comprising the steps of: generating background moving-image data whereinan area in which a still image is rendered is defined as a mask area ina number of frames of a background image constituting a backgroundmoving image; and defining a still-image rendering area in associationwith the mask area defined in the background image constituting thebackground moving image represented by the background moving-image datagenerated, and generating mask-image data representing a mask imagewherein an area from which the still-image rendering area has beenexcluded is defined as a mask area.

The second aspect of the present invention also provides a program forimplementing the above-described method of controlling theslideshow-data generating apparatus.

The second aspect of the present invention generates the backgroundmoving-image data and the mask-image data used in the first aspect ofthe present invention. Specifically, background moving-image datawherein an area in which a still image is rendered is defined as a maskarea is generated in a number of frames of a background imageconstituting a background moving image. Mask-image data representing amask image is generated. In the mask image, a still-image rendering areais defined in association with a mask area defined in the backgroundimage constituting the background moving image, and an area from whichthis still-image rendering area is excluded is defined as a mask area.

A slideshow can thus be generated by the first aspect of the presentinvention using the background moving-image data and the mask-image datagenerated in the second aspect of the invention.

The apparatus for generating the slideshow data may further comprisecalculating means for calculating a number of contiguous pixels in atleast one of the background image and mask image; and compressing meansfor compressing the background moving-image data and the mask-image databased upon the number of pixels calculated by the calculating means.Since the mask area and still-image rendering area often have identicalpixels, such as pixels representing white or black, that are contiguous,highly efficient compression can be achieved.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the electrical structure of aslideshow generating apparatus;

FIG. 2 illustrates the manner in which a sum image is generated;

FIG. 3 illustrates an example of scenario data;

FIG. 4 is a flowchart illustrating processing for generating a sum imageconstituting a slideshow;

FIG. 5 is a block diagram illustrating part of a moving-image combiningengine for generating a sum image;

FIG. 6 is a block diagram illustrating the electrical structure of anapparatus for generating slideshow data;

FIG. 7 is a flowchart illustrating processing for generating slideshowdata;

FIG. 8 illustrates the manner in which a combined image is generated;

FIG. 9 illustrates the manner in which a layer image is generated;

FIG. 10 illustrates an example of a background image;

FIGS. 11 and 12 show examples of mask images;

FIG. 13 is a flowchart illustrating processing for compressing a maskimage; and

FIG. 14 illustrates part of an array of pixels constituting a maskimage.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will now be described indetail with reference to the drawings.

FIG. 1 is a block diagram illustrating the electrical structure of aslideshow generating apparatus embodying the present invention.

The slideshow generating apparatus according to this embodimentgenerates a so-called advanced slideshow in which a still image isrendered on a background moving image. The still image is represented bystill-image data that has been recorded on a digital recording mediumsuch as a memory card carried about by the user [another digital mediumsuch as a CD (Compact Disk) may also be employed].

Background moving-image data, mask-image data, scenario data and aprogram for controlling operation described later have been storedbeforehand in a memory 1 of the slideshow generating apparatus. Thebackground moving-image data represents a moving image displayed as thebackground of a still image. The mask-image data is multiplied by astill image, whereby there is generated a product image to be added to abackground image that constitutes the background moving image. Thescenario data defines a position, etc., for rendering a still image,which is supplied by the user, in each background image of a number offrames constituting the background moving image. The backgroundmoving-image data, mask-image data and scenario data read from thememory 1 is input to a moving-image combining engine 3.

The slideshow generating apparatus is provided with a memory card reader4 in which a memory card carried about by the user is loaded.Still-image data that has been stored on the memory card is read andapplied to the moving-image combining engine 3.

An operation signal that is output from an operating unit 2 is appliedto the moving-image combining engine 3. Still-image data utilized in aslideshow is selected by the operating unit 2 from among still-imagedata that has been stored on the memory card.

Moving-image data for display, which represents the slideshow generatedin the moving-image combining engine 3, is applied to a display unit 5.A slideshow is thus displayed on the display screen of the display unit5.

The display moving-image data representing the slideshow generated maybe recorded on a recording medium such as a DVD (Digital VersatileDisk). In such case the slideshow generating apparatus would be providedwith a recording unit.

FIG. 2 illustrates a procedure for generating one frame constituting aslideshow.

A background moving image is composed of a number of frames of abackground image 10, as mentioned above. Two mask areas 11 and 12 havebeen defined in the background image 10 as areas in which still imagesare to be rendered. The mask areas 11 and 12 are so-called “black areas”(indicated by hatching) of pixel value 0. Accordingly, if other imagesare added to the mask areas 11 and 12, these superimposed images will bedisplayed.

In this embodiment, two frames of still images are rendered in one frameof the background image 10. To achieve this, the two mask areas 11 and12 have been defined in the background image 10, as mentioned above, andtwo frames of mask images 15 and 18 are prepared. A still-imagerendering area 16 in which a still image is to be rendered has beendefined in the first mask image 15. The area other than the still-imagerendering area 16 is adopted as a mask area 17 in the first mask image15. A still-image rendering area 19 in which a still image is to berendered has been defined in the second mask image 18 as well. The areaother than the still-image rendering area 19 is adopted as a mask area20 in the second mask image 18.

The still-image rendering areas 16 and 19 in the mask areas 15 and 18,respectively, are so-called “white areas” of pixel value 255 (in case of8-bit representation). It goes without saying that it will suffice ifthe still-image rendering areas 16 and 19 are pixels all of the samevalue other than 0, and these areas need not necessarily be white areasof pixel value 255.

A first still image 21 by which the first mask image 15 is multiplied isrepresented by still-image data that has been read from a memory card.The position of an image portion 22 of the still image has been decidedby scenario data regarding a background image to be combined. The imageportion 22 of the first still image 21 corresponds to the still-imagerendering area 16 of the first mask image 15, and an image portion 23from which the image portion 22 of the still image is excludedcorresponds to the mask area 17 of the first mask image 15. Similarly, asecond still image 24 by which the second mask image 18 is multiplied isrepresented by still-image data that has been read from a memory card.The position of an image portion 25 of the still image has been decidedby scenario data regarding a background image to be combined. The imageportion 25 of the second still image 24 corresponds to the still-imagerendering area 19 of the second mask image 18, and an image portion 26from which the image portion 25 of the still image is excludedcorresponds to the mask area 20 of the second mask image 18.

A first product image 30 is obtained by multiplying the first mask image15 by the positioned first still image 21. The first product image 30contains a still-image rendering area 31 and a mask area 32. The maskarea 17 of the first mask image 15 is of pixel value 0. By multiplyingthe first mask image 15 by the first still image 21, therefore, the maskarea 32 corresponding to the mask area 17 of the first mask image 15 isgenerated in the first product image 30. It will be understood thatsince the still-image rendering area 16 of the first mask image 15 is awhite area, the still-image portion 22 of the first still image 21appears in the still-image rendering area 31 of the first product image30. Similarly, a second product image 33 is obtained by multiplying thesecond mask image 18 by the positioned first still image 24. The secondproduct image 33 contains a mask area 35 corresponding to the mask area20 of the second mask image 18, and a still-image rendering area 34corresponding to the still-image portion 25 of the second still image24.

If the background image 10, the first product image 30 and the secondproduct image 33 are added, a sum image 40 is obtained. The sum image 40contains a first still-image area 41 in which the still-image portion 22of the first still image 21 appears, a second still-image area 42 inwhich the still-image portion 25 of the second still image 24 appears,and a background image area 43 in which an image of the backgroundportion of the background image 10 appears. Thus, an image (the sumimage 40) constituting one frame of a slideshow is generated. Bysimilarly generating images with regard to other frames, displaymoving-image data for displaying a slideshow is obtained. Owing to aframe-to-frame change in the positions of the first still-image area 41,second still-image area 42 and background image area 43 constituting thesum image 40, these frames are displayed successively to present aslideshow.

Since images obtained from a plurality of frames of still images arerepresented in one frame in the sum image generated, a sophisticatedslideshow is the result. In particular, it will suffice to simply addthe background image 10, first product image 30 and second product image33, and the order in which these are added (the order in which theimages are superimposed in a case where images are superimposed) doesnot matter. This means that the structure of the circuitry forgenerating the sum image is comparatively simple.

FIG. 3 illustrates an example of scenario data.

Scenario data defines the rendering of a still image in one frame of animage, as mentioned above. A rendering position number, combiningposition X, combining position Y, image width, image height and angle ofrotation are defined in correspondence with the frame number of theimage of each frame constituting the slideshow.

The rendering position number is a number that identifies the renderingposition of a still image in one frame of an image constituting aslideshow. It will be understood that since rendering position numberscorresponding to Frame No. 1 are 1 and 2, still images rendered in theimage of Frame No. 1 are two in number.

The combining positions X and Y define the rendering position of a stillimage. The still image is positioned in such a manner that theupper-left corner of the still image to be rendered will conform to thecoordinates stipulated by the combining positions X and Y.

Image width and height define the size of the still image. The stillimage is subjected to enlargement or reduction processing in such amanner that the still image to be rendered will fit into the areastipulated by the width and height of the image.

Angle of rotation defines the angle of rotation of the still image andindicates the relative angle of rotation with respect to the renderingarea of the still image displayed in the rendering area of the stillimage stipulated by the above-mentioned combining position X, combiningposition Y, image width and image height.

By way of example, if the sum image described in FIG. 2 is the secondframe, then the still-image portion 22 of the first still image 21 isspecified by Rendering Position No. 1, and the combining position (X,Y)of this image portion is represented by (X1,Y1). The coordinates of theupper-left corner of the still-image portion 22 conform to thiscombining position (X1,Y1). Further, the still-image portion 22 isdefined by image width W1 and image height H1, and the angle of rotationis expressed by θ1. Similarly, the still-image portion 25 of the secondstill image 24 is specified by Rendering Position No. 2, and thecoordinates of the upper-left corner conform to the combining position(X2,Y2). Furthermore, the still-image portion 25 is defined by imagewidth W2 and height H2, and the angle of rotation is expressed by θ2.

FIG. 4 is a flowchart illustrating processing for generating a sum imageconstituting a slideshow.

First, the background image is read (step 51), then scenario datacorresponding to the read background image is read (step 52). Next,still-image data representing the first frame of a still image to berendered on this background image is read (step 53). Enlargement,reduction, rotation and positioning of the still image are carried outin accordance with the scenario data (step 54). The mask image and thestill image that has undergone positioning and the like are multipliedtogether to obtain a product image (step 55). The product image obtainedand the background image are added to obtain a sum image (step 56). Ifthere is a still image to be rendered on the sum image, one frame of thesum image will be incomplete (“NO” at step 57) and therefore theprocessing of steps 53 to 56 is repeated.

If there is no still image to be rendered on the sum image obtained,then it is construed that one frame of the sum image has been completed(“YES” at step 57) and the image data representing the sum imageobtained is written temporarily to the memory of the moving-imagecombining engine (step 58).

By repeating the processing of steps 51 to 58 with regard to allbackground images constituting the background moving image (“NO” at step59), all sum images constituting the slideshow are obtained (“YES” atstep 59).

FIG. 5 is a block diagram illustrating part of a moving-image combiningengine for generating the sum image described above.

Data representing a background image is applied to an adding circuit 62via a changeover circuit 63. Further, data representing a mask image andstill-image data representing a still image that has been positioned isinput to a multiplying circuit 61, whereby the items of data aremultiplied together. Image data representing the product image is outputfrom the multiplying circuit 61 and input to the adding circuit 62. Thelatter adds the product image and the background image to obtain the sumimage. The data representing the sum image is applied to the changeovercircuit 63. In a case where a still image is rendered on the sum imageobtained (i.e., in a case where there are a plurality of still-imageportions), the changeover circuit 63 is changed over in such a mannerthat the sum-image data that has been output from the adding circuit 62is input to the adding circuit 62. As a result, image data representingthe product image of the next frame that will be output from themultiplying circuit 61 is input to the adding circuit 62 and thus isfurther added to the sum image. As illustrated in FIG. 2, a sum image inwhich a plurality of still-image portions are contained in one frame isobtained. The circuits 61 to 63 are controlled by a control unit (notshown), which is included in the moving-image combining engine 3, so asto obtain a number of frames of sum images.

FIGS. 6 to 12 illustrate the generation of the above-describedbackground image 10, first mask image 15 and second mask image 17.

Image data representing a plurality of layer images (the details will bedescribed later with reference to FIG. 8) for which the above-describedsum image is obtained by superimposing of images from the lowermostlayer has been stored in a memory 71. The image data representing theplurality of layer images is applied to a background moving-image/maskimage generating unit 72. An operating signal from an operating unit 73also is applied to the background moving-image/mask image generatingunit 72.

The background image 10, first mask image 15 and second mask image 17are generated in the background moving-image/mask image generating unit72. The generated background image 10 and other images are displayed ona display unit 75, whereby the images are checked by the operator. Theimage data representing the generated background image 10 and otherimage is compressed in a compressing circuit 76 (the details will bedescribed in conjunction with FIGS. 13 and 14). The image data that hasbeen compressed is recorded on a DVD (not shown) by a DVD recorder 77. Aslideshow can be generated by loading the DVD into the slideshowgenerating apparatus. Of course, the image data representing thebackground image 10 and other images need not necessarily be compressed.

FIG. 7 is a flowchart illustrating processing for generating image datarepresenting the background image 10, etc. FIG. 8 illustrates an exampleof layer images, etc., used in order to generate image data representingthe background image 10, etc.

A background layer image 90, first layer image 91, second layer image92, third layer image 93 and fourth layer image 94 are prepared. Theseimages 90 to 94 are superimposed in the order mentioned, whereby thereis generated a combined image 95 corresponding to the sum image 40 (seeFIG. 2) that is to become the above-mentioned target, as illustrated onthe right side of FIG. 8.

The background layer image 90 is one in which the background-imageportion from which the mask areas 11 and 12 of the above-describedbackground image 10 (see FIG. 2) have been excluded is being displayedover the entirety of the screen. The first layer image 91 is positionedat the same position as that of the first still image 21 (see FIG. 2)positioned as described above and contains any still-image portionhaving a shape identical with that of the still-image rendering area 16of the first mask image 15. The second layer image 92, which representsa decorative image displayed on the background image 10, is displayed onthe still image 21 positioned as set forth above. The third layer image93 is positioned at the same position as that of the second still image24 (see FIG. 2) positioned as described above and contains anystill-image portion having a shape identical with that of thestill-image rendering area 19 of the second mask image 18. The fourthlayer image 94, which also represents a decorative image displayed onthe background image 10 in a manner similar to that of the second layerimage 92, embellishes the second still image 24 positioned as set forthabove.

Among the layer images 90 to 94, the third layer image 93 is obtained bypreparing any still image 96, which has been positioned at a positionidentical with that of the second still image 24 (see FIG. 2) on which astill-image portion 97 has been positioned, and a mask image 98 havingan area 99 corresponding to the still-image rendering area of thebackground image 10, and masking the still image 96 by the mask image98.

First, the still-image portions (the still-image portions of the layerimage 91 and the layer image 94) among the layer images 90 to 94 areassumed to be black. The background layer image 90, the first layerimage 91 in which the background-image area is assumed to be black, thesecond layer image 92, the third layer image 93 in which the still-imageportion is assumed to be black and the fourth layer image 94 aresuperimposed in the order mentioned. This results in the generation ofthe background image 10 shown in FIG. 10 (step 81).

Next, the still-image portion of one layer image (e.g., the first layerimage 91) that contains a still-image portion is assumed to be white,the still-image portions with regard to the other layer images areassumed to be black, and all of these layer images are superimposed inthe following order: the background layer image 90, the first layerimage 91, the second layer image 92, the third layer image 93 and thefourth layer image 94. This results in the generation of the first maskimage 15 shown in FIG. 11 (step 82).

If it is necessary to generate another mask image (as in a case where aplurality of mask images are generated) (“YES” at step 83), the layerimage of the still-image portion assumed to be a white area is changedand the processing of step 82 is executed again. By way of example, thestill-image portion of the third layer image 93 is adopted as a whitearea, the image portions regarding other layer images are assumed to beblack, and all of these layer images 90 to 94 are superimposed in thefollowing order: the background layer image 90, first layer image 91,second layer image 92, third layer image 93 and fourth layer image 94,whereby the second mask image 17 shown in FIG. 12 is generated (thesecond mask image 17 and the mask image 98 shown in FIG. 9 merely happento coincide and are not always the same).

Thus, all of the background images and mask images of the multiplicityof frames that constitute the background moving image are generated insimilar fashion.

In a case where one frame of an image constituting a slideshow isgenerated by superimposing layers from the lowermost layer, as in theprior art, layer images of a multiplicity of frames are necessary. Inthis embodiment, however, one frame of an image (the sum image)constituting a slideshow can be generated merely by using background andmask images, as illustrated in FIG. 2.

The combined image 95 shown on the right side of FIG. 8 can also beutilized to generate the background image 10, first mask image 15 andsecond mask image 17 illustrated in FIGS. 10, 11 and 12. In a case wherethe background image 10 is generated, all of the still-image portions ofthe combined image 95 are adopted as mask areas. If this is done, thebackground image 10 shown in FIG. 10 is obtained. Further, in thecombined image 95, if a still-image rendering area is generated byadopting a white area with regard to a specific still-image portion anda mask area that will become a black area is generated with regard toportions other than the specific still-image portion, then the firstmask image 15 shown in FIG. 11 or the second mask image 17 shown in FIG.12 will be generated.

FIGS. 13 and 14 are useful in describing a method of compressing datarepresenting a mask image generated in the manner set forth above (thebackground image can also be compressed in a similar manner). FIG. 13 isa flowchart illustrating compression processing.

First, a mask image is read (step 101) and it is determined whether allareas of the read mask image are black (i.e., whether it is an image ofa frame that does not contain a still image) (step 102). If all areasare black (“YES” at step 102), then a frame-skip code indicating thatall areas are black is output (step 103). If all areas are not black(“NO” at step 102), then the mask image is read one pixel at a time(step 104).

The reading of pixels one pixel at a time is repeated until three ormore successive identical pixels (e.g., pixels representing white,pixels representing black, etc.) are found. If three or more successiveidentical pixels are found (“YES” at step 105), a non-successive code,number of pixels and pixel values of each of these pixels are outputwith regard to pixels up to those that precede the three or moresuccessive identical pixels (step 106).

The reading of pixels continues. If a different pixel is found (“YES” atstep 107), then a successive code, number of pixels and pixel values ofeach of these pixels are output with regard to identical pixels up tothose that prevailed prior to the discovery of the different pixel (step108).

The processing of steps 104 to 108 is repeated until the reading ofpixels ends with regard to all mask images (step 109).

FIG. 14 illustrates part of a pixel array of a mask image. Pixels 110are white pixels, and pixels 111 indicated by hatching are black pixels.

The first, second, fourth and sixth through tenth pixels 110 are thewhite pixels, and the third, fifth and eleventh pixels 111 are the blackpixels.

In a case where pixels have been read in order starting from the firstpixel, three successive identical pixels 110 are found if pixels areread up to the eighth pixel. Accordingly, with regard to the first tofifth pixels, which are pixels that precede the three successiveidentical pixels from the sixth to the eighth, a non-successive code,the number (i.e., five) of pixels and the pixel values of each of thesepixels are output.

If the reading of pixels continues, the eleventh pixel 111 becomes ablack pixel and thus a pixel appears that is different from the whitepixels 110, which are the identical pixels up to this black pixel 111.Accordingly, a successive code, number of pixels and the identical pixelvalues are output with regard to the sixth to tenth pixels.

Since identical pixels often appear in succession in a mask image,highly efficient compression can be performed.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

1. A slideshow generating apparatus comprising: a backgroundmoving-image storage device for storing background moving-image datarepresenting a background moving image composed of a number of frames ofa background image wherein an area in which a still image is renderedhas been defined as a mask area; a still-image data input device forinputting still-image data; a scenario data storage device for storingscenario data that defines a position corresponding to the mask area inthe background image, said position being one at which the still imagerepresented by the still-image data that has been input from saidstill-image data input device is rendered; a positioning device forpositioning the still image, which is represented by the still-imagedata that has been input from said still-image data input device, at theposition represented by the scenario data stored in said scenario datastorage device; a mask-image data storage device for storing mask-imagedata representing a mask image in which a still-image rendering area hasbeen defined in association with the mask area of the background image,an area from which the still-image rendering area has been excludedbeing defined as a mask area; and a moving-image combining device forgenerating moving-image data for display by repeatedly executing, withregard to the number of frames of the background image, processing thatcombines the background image constituting the background moving imagerepresented by the background moving-image data that has been stored insaid background moving-image data storage device, the still image thathas been positioned by said positioning device, and the mask imagerepresented by the mask-image data that has been stored in said maskimage-data storage device.
 2. The apparatus according to claim 1,wherein said moving-image combining device includes: a multiplyingcircuit for multiplying the mask image and the still image that has beenpositioned by said positioning device, thereby generating a productimage; an adding circuit for adding the background image and the productimage generated by said multiplying circuit; and a controller forcontrolling said multiplying circuit and said adding circuit so as torepeat, with regard to the number of frames of the background image,multiplication processing performed in said multiplying circuit andaddition processing performed in said adding circuit.
 3. A method ofcontrolling a slideshow generating apparatus, comprising the steps of:storing background moving-image data representing a background movingimage composed of a number of frames of a background image wherein anarea in which a still image is rendered has been defined as a mask area;storing mask-image data representing a mask image in which a still-imagerendering area has been defined in association with the mask area of thebackground image, an area from which the still-image rendering area hasbeen excluded being defined as a mask area; inputting still-image data;storing scenario data that defines a position corresponding to the maskarea in the background image, said position being one at which the stillimage represented by the still-image data that has been input isrendered; positioning the still image, which is represented by thestill-image data that has been input, at the position represented by thescenario data stored; and generating moving-image data for display byrepeatedly executing, with regard to the number of frames of thebackground image, processing that combines the background imageconstituting the background moving image represented by the backgroundmoving-image data that has been stored, the still image that has beenpositioned, and the mask image represented by the mask-image data thathas been stored.
 4. A computer-readable medium storing a program forcontrolling a slideshow generating apparatus so as to cause theapparatus to: store background moving-image data representing abackground moving image composed of a number of frames of a backgroundimage wherein an area in which a still image is rendered has beendefined as a mask area; store mask-image data representing a mask imagein which a still-image rendering area has been defined in associationwith the mask area of the background image, an area from which thestill-image rendering area has been excluded being defined as a maskarea; input still-image data; store scenario data that defines aposition corresponding to the mask area in the background image, saidposition being one at which the still image represented by thestill-image data that has been input is rendered; position the stillimage, which is represented by the still-image data that has been input,at the position represented by the scenario data stored; and generatemoving-image data for display by repeatedly executing, with regard tothe number of frames of the background image, processing that combinesthe background image constituting the background moving imagerepresented by the background moving-image data that has been stored,the still image that has been positioned, and the mask image representedby the mask-image data that has been stored.